1. Field of the Invention
The present invention relates to a press device for treating a fibrous pulp sheet, in particular, to drain, smooth, or calibrate, e.g., a paper web in a paper machine, in a press nip (gap; opening) formed between a shoe press roll and a mating roll.
2. Discussion of Background Information
In treating fibrous pulp sheets, and, in particular, in draining paper webs, shoe press rolls act together with a mating roll to create a press nip or gap. In certain instances, the mating roll can be formed by another shoe press roll. To ensure gentle draining of the web, and to meet increasing demands of dry content, smoothness, volume, etc., development of these types of devices generally tends toward increasing the shoe lengths. In this manner, a high press impetus or force is to be achieved in the press nip with a minimum pressure gradient and the lowest possible maximum pressure. With increasing press shoe and press are lengths, to prevent a very extreme local bending of the press sleeve acting together with the press shoe, the press nip, subsequent to the press area, should be flattened. This is the general principle of creating a press nip between two shoe press rolls. However, this arrangement also requires new concepts in the drive mechanism.